Underwater explosives
The way they used explosives underwater would have instantly crushed the suits from the following shockwave. especially in deep underwater conditions. explosions under water are hell of a dangerous thing because unlike air, in water the shockwave does not dissipate so the suits would actually feel the full force of the explosion. and in the movie they clearly stood close to the explosion when blasting a rock.
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Applied Science? All science is applied. Eventually.