diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index b0af9f5f..2b0d96ef 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -1265,19 +1265,17 @@ Script.prototype.execute = function execute(stack, flags, tx, index, version) {
       switch (op) {
         case opcodes.OP_IF:
         case opcodes.OP_NOTIF: {
+          val = false;
           if (negate === 0) {
             if (stack.length < 1)
               throw new ScriptError('UNBALANCED_CONDITIONAL', op, ip);
             val = Script.bool(stack.pop());
             if (op === opcodes.OP_NOTIF)
               val = !val;
-            state.push(val);
-            if (!val)
-              negate++;
-          } else {
-            state.push(false);
-            negate++;
           }
+          state.push(val);
+          if (!val)
+            negate++;
           break;
         }
         case opcodes.OP_ELSE: {
@@ -1302,7 +1300,7 @@ Script.prototype.execute = function execute(stack, flags, tx, index, version) {
           throw new ScriptError('BAD_OPCODE', op, ip);
         }
         default: {
-          assert.fatal(false, 'Fatal script error.');
+          assert(false, 'Fatal script error.');
         }
       }
       continue;
@@ -1550,7 +1548,7 @@ Script.prototype.execute = function execute(stack, flags, tx, index, version) {
             n = n.cmpn(0) !== 0;
             break;
           default:
-            assert.fatal(false, 'Fatal script error.');
+            assert(false, 'Fatal script error.');
         }
         if (typeof n === 'boolean')
           n = new bn(n ? 1 : 0);
@@ -1659,7 +1657,7 @@ Script.prototype.execute = function execute(stack, flags, tx, index, version) {
                 n = n1.cmp(n2) > 0 ? n1 : n2;
                 break;
               default:
-                assert.fatal(false, 'Fatal script error.');
+                assert(false, 'Fatal script error.');
             }
             if (typeof n === 'boolean')
               n = new bn(n ? 1 : 0);