On Scorpion Season 4 Episode 18, the team is focused on one mission: getting Happy pregnant. Specifically, they need to orchestrate the handoff of Toby's sperm at the fertility clinic.

Team Scorpion has a plan, and it's running smoothly until Walter decides to make a pit stop at a bank.

Toby realizes that the bank is currently being robbed, and despite his best efforts, he and Walter don't make it out of the bank safely. The bank robbers put them in the break room with the other hostages. 

Cabe rounds up the local cops to make sure they don't answer any calls regarding the bank to ensure the hostages' safety. Happy and Paige set up in a doctor's office at the fertility clinic, and Sly and Florence are running things from the garage.

The plan becomes getting Toby's sperm out safely, so Cabe can take it to the fertility clinic. Toby uses the drive-thru shoot, but the sperm capsule gets stuck.

Team Scorpion realizes that if they can explode the dye packs the robbers have been removing from the stacks of money, then the explosion could provide enough force to get the sperm capsule through the shoot, but time is running out. 

The issue is the signal that's supposed to trigger the explosion isn't reaching the bank all because of window blinds. It's the people you don't expect that end up screwing you over in the end.

Walter must make a daring escape out into the lobby in order to raise the blinds. It's a close call, but everything works out, even though Walter gets captured by one of the robbers.

The dye packs explode. Cabe and the authorities come in and save the day, and Toby somehow manages to run outside in time to catch his sperm that's shooting out of the drive-thru shoot.

Now, all we have to do is wait to see if the fertilization takes, and Happy becomes pregnant.