diff --git a/runner/lib/main.js b/runner/lib/main.js
index 7d8c2b2..32222fa 100644
--- a/runner/lib/main.js
+++ b/runner/lib/main.js
@@ -7,6 +7,8 @@ import { promisify } from 'util';
 import {
   pipeline as pipelineCallback,
   finished as finishedCallback,
+  Readable,
+  PassThrough,
 } from 'stream';
 
 import yargsParser from 'yargs-parser';
@@ -295,6 +297,9 @@ const main = async (progName, rawArgs, powers) => {
       );
       chainStorageLocation = runChainResult.storageLocation;
 
+      const slogLinesStream = Readable.from(runChainResult.slogLines);
+      const slogLines = new PassThrough({ objectMode: true });
+
       const slogOutput = zlib.createGzip({
         level: zlib.constants.Z_BEST_COMPRESSION,
       });
@@ -304,13 +309,48 @@ const main = async (progName, rawArgs, powers) => {
       await fsStreamReady(slogOutputWriteStream);
       // const slogOutput = slogOutputWriteStream;
       // const slogOutputPipeResult = finished(slogOutput);
-      const slogOutputPipeResult = pipeline(slogOutput, slogOutputWriteStream);
+      slogLinesStream.pipe(slogLines);
+      const slogOutputPipeResult = pipeline(
+        slogLinesStream,
+        slogOutput,
+        slogOutputWriteStream,
+      );
+
+      /** @type {import("./sdk/promise-kit.js").PromiseRecord<void>} */
+      const firstBlockDoneKit = makePromiseKit();
+      /** @type {(() => void) | null} */
+      let resolveFirstBlockDone = firstBlockDoneKit.resolve;
 
       /** @type {import("./sdk/promise-kit.js").PromiseRecord<void>} */
-      const {
-        promise: chainFirstEmptyBlock,
-        resolve: resolveFirstEmptyBlock,
-      } = makePromiseKit();
+      const firstEmptyBlockKit = makePromiseKit();
+      /** @type {(() => void) | null} */
+      let resolveFirstEmptyBlock = firstEmptyBlockKit.resolve;
+
+      let blockCount = 0;
+
+      const notifier = {
+        /** @param {{blockHeight: number, slogLines: number}} block */
+        blockDone(block) {
+          blockCount += 1;
+
+          if (resolveFirstBlockDone) {
+            resolveFirstBlockDone();
+            resolveFirstBlockDone = null;
+          }
+
+          if (resolveFirstEmptyBlock) {
+            if (block.slogLines === 0 || blockCount > 10) {
+              if (block.slogLines === 0) {
+                logPerfEvent('stage-first-empty-block', {
+                  block: block.blockHeight,
+                });
+              }
+              resolveFirstEmptyBlock();
+              resolveFirstEmptyBlock = null;
+            }
+          }
+        },
+      };
 
       const chainMonitor = makeChainMonitor(runChainResult, {
         ...makeConsole('monitor-chain', out, err),
@@ -320,14 +360,16 @@ const main = async (progName, rawArgs, powers) => {
       });
       chainMonitor.start(monitorInterval);
 
-      const slogMonitorDone = monitorSlog(runChainResult, {
-        ...makeConsole('monitor-slog', out, err),
-        resolveFirstEmptyBlock,
-        chainMonitor,
-        localTimeSource: timeSource,
-        logPerfEvent,
-        slogOutput,
-      });
+      const slogMonitorDone = monitorSlog(
+        { slogLines },
+        {
+          ...makeConsole('monitor-slog', out, err),
+          notifier,
+          chainMonitor,
+          localTimeSource: timeSource,
+          logPerfEvent,
+        },
+      );
 
       await aggregateTryFinally(
         async () => {
@@ -335,7 +377,11 @@ const main = async (progName, rawArgs, powers) => {
           logPerfEvent('chain-ready');
           stageConsole.log('Chain ready');
 
-          await orInterrupt(chainFirstEmptyBlock);
+          await Promise.race([
+            slogMonitorDone,
+            orInterrupt(firstBlockDoneKit.promise),
+          ]);
+          await orInterrupt(firstEmptyBlockKit.promise);
 
           await nextStep(done);
         },
diff --git a/runner/lib/monitor/slog-monitor.js b/runner/lib/monitor/slog-monitor.js
index 18bdceb..6721e36 100644
--- a/runner/lib/monitor/slog-monitor.js
+++ b/runner/lib/monitor/slog-monitor.js
@@ -94,36 +94,23 @@ const slogEventRE = filterSlogEvent([
 /**
  * @param {Pick<import("../tasks/types.js").RunChainInfo, 'slogLines'>} chainInfo
  * @param {Object} param1
- * @param {() => void} param1.resolveFirstEmptyBlock
+ * @param {{blockDone(stats: {blockHeight: number, slogLines: number}): void}} [param1.notifier]
  * @param {ReturnType<import("./chain-monitor").makeChainMonitor>} [param1.chainMonitor]
  * @param {import("../stats/types.js").LogPerfEvent} param1.logPerfEvent
  * @param {import("../helpers/time.js").TimeSource} [param1.localTimeSource]
- * @param {import("stream").Writable} [param1.slogOutput]
  * @param {Console} param1.console
  */
 export const monitorSlog = async (
   { slogLines },
-  {
-    resolveFirstEmptyBlock,
-    chainMonitor,
-    localTimeSource,
-    logPerfEvent,
-    slogOutput,
-    console,
-  },
+  { notifier, chainMonitor, localTimeSource, logPerfEvent, console },
 ) => {
   /** @type {number | null}  */
   let slogStart = null;
 
   let slogBlocksSeen = 0;
-  let slogEmptyBlocksSeen = 0;
   let slogLinesInBlock = 0;
 
   for await (const line of slogLines) {
-    if (slogOutput) {
-      slogOutput.write(line);
-    }
-
     if (slogStart == null && chainMonitor) {
       // TODO: figure out a better way
       // There is a risk we could be late to the party here, with the chain
@@ -193,12 +180,8 @@ export const monitorSlog = async (
         if (!slogBlocksSeen) {
           logPerfEvent('stage-first-block', { block: blockHeight });
           if (chainMonitor) {
-            await chainMonitor.logProcessUsage().catch((usageErr) => {
-              // Abuse first empty block as it will be awaited before monitorChain
-              // And won't abruptly end our monitor
-              // @ts-ignore resolving with a rejected promise is still "void" ;)
-              resolveFirstEmptyBlock(Promise.reject(usageErr));
-            });
+            // This will abruptly end the monitor if there is an error
+            await chainMonitor.logProcessUsage();
           }
         }
         console.log('begin-block', blockHeight);
@@ -223,15 +206,8 @@ export const monitorSlog = async (
           const { blockHeight = 0 } = event;
           // Finish line itself doesn't count
           slogLinesInBlock -= 1;
-          if (slogLinesInBlock === 0) {
-            if (!slogEmptyBlocksSeen) {
-              logPerfEvent('stage-first-empty-block', {
-                block: blockHeight,
-              });
-              resolveFirstEmptyBlock();
-            }
-            slogEmptyBlocksSeen += 1;
-          }
+          notifier &&
+            notifier.blockDone({ blockHeight, slogLines: slogLinesInBlock });
 
           console.log(
             'end-block',