The team had to outwit their deranged previous teammate after the latter abducted Toby and posed a threat to his life in the "Scorpion" season 2 episode 24, the season finale.

"Scorpion" season 2 episode 24 is entitled "Toby or Not Toby." According to Spoilers Guide, the team had to consider and weigh things involving their ex-team member, Mark Collins, after he took Toby and threatened to kill him just to meet his devious demands.

If Collins' demands were met, which includes Walter's BBI research, he would advance his technology for him to be able to become a telepath and read things in people's minds. The team found that Collins' hideout was via ham radio frequencies, so Walter had to decide if they would seize him or allow him to escape and dismount his booby trap, with Toby close to dying.

In the season finale, Walter also caught Collins on a bus heading to South Carolina, the cradle of the latter's childhood home. Also, the episode saw Sylvester allowed Toby's marriage proposal to Happy, but the latter was keeping a marriage secret of her own.

Walter also thought sensibly on Paige, with his mind telling him that he loved the latter. The episode saw the former stop the woman from spending her weekend with Tim at a jazz festival and meet her in Lake Tahoe.

"Scorpion" season 2 finale follows episode 23, entitled "Chernobyl Intentions." According to Spoilers Guide, the episode saw Team Scorpion go to Chernobyl to fix the deteriorating nuclear reactor before it adversely affects the locale with its meltdown. The team also had to rescue Paige and Sylvester, as the two were trapped inside.

"Scorpion" season 2 episode 23, "Chernobyl Intentions," aired on Apr. 18 while episode 24 (season finale), "Toby or Not Toby," aired on Apr. 25.