He does need them if they're a team!! And like it or not, right now they are. Lexa watches as Bellamy takes out the guarding mage and, whether he likes this or not, gives him a tiny little nod of approval. She can recognize nice work when she sees it.

She steps past the mage as Bellamy eases his body to the ground, and then stops at the tunnel exit, just shy of stepping into view of the rest of the battle. She spins the blade in her off hand and wiggles it, re-setting her grip around the hilt as she turns to Bellamy and, finding he's back on his feet, counts off with the fingers of her other hand: one, two. It's a rudimentary way to coordinate her attack with his, but it will have to do.

One: she moves silently out of the tunnel, both swords spun in her hands now, everite blades flashing. She scans the area for anyone diverting to intercept her, for Maris noticing--

Two: her focus narrows to her target as she speeds up, tunnel-visioned as, hopefully, Bellamy's Templar abilities slam down on the head mage. It should happen just now, just as she sprints the last step up to Maris and lunges to drive her blade into his heart from behind.