diff --git a/src/p_map.c b/src/p_map.c
index f6bbda527..075a80090 100644
--- a/src/p_map.c
+++ b/src/p_map.c
@@ -3519,8 +3519,7 @@ void P_SlideMoveOLD(mobj_t *mo)
 
 	memset(&junk, 0x00, sizeof(junk));
 
-	if (P_MobjWasRemoved(mo))
-		return;
+	I_Assert(!P_MobjWasRemoved(mo));
 
 	if (g_tm.hitthing && mo->z + mo->height > g_tm.hitthing->z && mo->z < g_tm.hitthing->z + g_tm.hitthing->height)
 	{