As a whole, the reptiles have a problem. The majority of them have legs sprawled away from the body, so when they move, they would suffer a kind of problem called "Carrier's constraint", and what that means is that the reptiles flex their bodies sideways as they move, expanding one lung and deflating the other, preventing the animal from moving and breathing at the same time.
The one notable exception to this are the alligators and the crocodiles, who have a "bent knee" posture, encouraging a "high walk", a kind of movement more similar to how a mammal moves than how a lizard moves.
In this alternate scenario, two other types of reptiles position their legs for the high walks:
Testudinidae, the tortoises...
...and Varanidae, the monitor lizards. (The bonus is that they use their throat muscles to gulp air, thus improving stamina.)
Add the high-walk posture on these two groups. Would it be help the tortoises to support their heavy carapace shells and the monitor lizards to add to their already efficient predatory standards?