diff --git a/content/CONTROLS.MAP b/content/CONTROLS.MAP
index 57a8e91..3c9ebad 100644
--- a/content/CONTROLS.MAP
+++ b/content/CONTROLS.MAP
@@ -165,6 +165,12 @@ pad Start action ModeCycle
 pad RightThumb action DisplayCycle
 pad Back  action Valve
 
+# COOLANT FLUSH -- HELD key dumps reservoir coolant into the loops
+# (Reservoir InjectCoolant, msg 4).  The tank drains while held; with the
+# tank empty the loops burn coolant with no refill -- run hot long enough
+# and the bank drops below 5%, which ARMS the eject (Panic lights).
+key G action Flush
+
 # PANIC / EJECT -- the punch-out (Mech msg 0x19).  Only fires on a CRIPPLED
 # mech (no generators, coolant leaked below 5%, or leg-gimped novice) -- a
 # healthy mech refuses the button, so a stray press is a no-op.
diff --git a/game/reconstructed/mech4.cpp b/game/reconstructed/mech4.cpp
index 1b47a3b..a38e070 100644
--- a/game/reconstructed/mech4.cpp
+++ b/game/reconstructed/mech4.cpp
@@ -6724,7 +6724,15 @@ void
 			++s_ftFrame;
 			int t0 = atoi(getenv("BT_FLUSH_TEST"));
 			if (t0 < 1) t0 = 600;
-			gBTFlushKey = (s_ftFrame >= t0 && s_ftFrame < t0 + 60) ? 1 : 0;
+			// BT_FLUSH_HOLD=<frames> (default 60): the eject firsthand recipe
+			// needs a tank-dry hold, not just the 1 s edge test.
+			static int s_ftHold = 0;
+			if (s_ftHold == 0)
+			{
+				const char *h = getenv("BT_FLUSH_HOLD");
+				s_ftHold = (h && atoi(h) > 0) ? atoi(h) : 60;
+			}
+			gBTFlushKey = (s_ftFrame >= t0 && s_ftFrame < t0 + s_ftHold) ? 1 : 0;
 		}
 
 		// Gitea #46 scripted verify (BT_BAYTEST=<frame>): at the given sim frame