One of the lugs on the coil had 2 red wires wires. That is the power side and they are wired from one coil to the next. If you just cut the 2 red wires off the coil, you broke the power supply chain to the downstream coils which will stop them from working.

Connect the wires back up to the coil.

Check the problem still exists.

Remove J13 from the driver board. This is the special switch input connector (fires the pops, slings, etc).

If the coil still locks on, you have a problem with the driver board.

If the coil does not lock on, the problem is in the trigger switch or wiring.

J13 is the switch input to the driver board for special solenoids.
J12 is the drive.

When trying to troubleshooting a locked coil, disconnecting the switch input connector, J13 can isolate the problem to the board or the switches. Disconnecting J12 only disconnects the drive transistor from the solenoids stopping the coil from locking on but really doesn't tell you anything.

I would replace it with another 13N10L MOSFET.

Before you do, check the resistance of that coil. It should be around 5.3 ohms. If you get zero or close to it, reverse the polarity of the meter leads and measure again.

If the coil resistance is good, make sure to replace the diode on that coil and make sure it is installed in the correct orientation. I suspect the diode is bad and what killed the MOSFET.

Next transistor you need to remove, try cutting the body of the transistor off the legs first. Then you can desolder and remove one leg at at time.

Remove the 3 nuts that hold the coil bracket to the bottom of the playfield. be careful to catch the spring on the plunger as you remove the bracket.

Once that is removed, you remove screws "A" and you can remove the old coil and mount the new coil and sleeve in place.

Reverse above (remember the spring) to reassemble.

Oh, one other thing:

Make sure your new coil has a diode installed. Pay careful attention to the lugs you solder the wires - Double red wire (power supply) goes to the lug with the banded side of the diode.

Awesome! Congratulations on the fix!